Enter solar system assumptions
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Example data table
| Example input | Value | Calculated output | Value |
|---|---|---|---|
| Panel count | 20 | DC capacity | 10.80 kW |
| Panel wattage | 540.00 W | Daily energy | 52.58 kWh |
| Peak sun hours | 5.80 h/day | Monthly average | 1,600.42 kWh |
| Tilt factor | 1.02 | Annual energy | 19,205.07 kWh |
| Availability | 99.00% | Specific yield | 1,778.25 kWh/kWp |
| Grid emission factor | 0.45 kg/kWh | Annual CO2 offset | 8,642.28 kg |
Formula used
1) DC capacity: DC Capacity (kW) = Panel Count × Panel Wattage ÷ 1000
2) Temperature factor: Temperature Factor = 1 + [Temperature Coefficient ÷ 100 × (Cell Temperature − 25)]
3) Combined loss factor: Multiply remaining fractions after soiling, shading, mismatch, DC wiring, inverter conversion, AC wiring, and availability effects.
4) Daily output: Daily Output (kWh) = DC Capacity × Peak Sun Hours × Tilt Factor × Azimuth Factor × Temperature Factor × Loss Factor × Bifacial Factor × Degradation Factor
5) Annual output: Sum normalized monthly values based on the daily output and month length.
6) Specific yield: Specific Yield = Annual Output ÷ DC Capacity
7) Capacity factor: Capacity Factor (%) = Annual Output ÷ (DC Capacity × 8760) × 100
8) Annual CO2 offset: Annual CO2 Offset = Annual Output × Grid Emission Factor
How to use this calculator
- Enter the number of modules, wattage per module, and area per module.
- Add your average peak sun hours for the site.
- Adjust tilt and azimuth factors to reflect mounting direction and orientation quality.
- Enter operating cell temperature and the panel temperature coefficient from the module datasheet.
- Add realistic system losses for soiling, shading, mismatch, DC wiring, AC wiring, and inverter efficiency.
- Set availability, degradation, system age, and optional bifacial gain.
- Press Calculate Output to show the result section below the header and above the form.
- Use the CSV and PDF buttons to export the computed summary and monthly production values.
FAQs
1) What does this calculator estimate?
It estimates daily, monthly, and annual solar array energy. It also shows peak AC power, specific yield, capacity factor, performance ratio, energy density, and carbon offset using your site and system assumptions.
2) Why are tilt and azimuth entered as factors?
Using factors keeps the tool flexible. A value near 1.00 means near-optimal orientation. Lower values represent less favorable tilt or compass direction without forcing a location-specific sun-position model.
3) How should I choose peak sun hours?
Use your site’s average daily solar resource on the panel plane. If you only know horizontal irradiation, convert it first or use a planning estimate from a trusted solar resource database.
4) What is the temperature coefficient?
It is the module power change per degree Celsius above or below standard test conditions. Most crystalline panels use a negative value, meaning hotter cells usually reduce available power.
5) Why does the chart show monthly variation?
The graph applies normalized seasonal multipliers around your average daily output. This creates a practical monthly profile while keeping your annual estimate anchored to the form inputs.
6) What is specific yield?
Specific yield is annual energy divided by installed DC capacity. It helps compare different systems on an equal basis, even when total capacity or module count changes.
7) Is the carbon offset value exact?
No. It is an estimate based on the emission factor you enter. Choose a factor that matches your local grid mix for a better planning value.
8) Can I use this for commercial systems?
Yes. The calculator works for rooftop and ground-mounted systems if your assumptions are realistic. For contracts or engineering signoff, validate results with site-specific irradiance, shading, and equipment models.